Checkboxes work a bit different, they have a value, but it's not what you have to set if you want to tick / enable a checkbox.
We've got a simple structure like this:
<input type="checkbox" id="myCheckbox">
If you then want to tick the checkbox using jQuery, you simply have to run this code:
Set the second parameter to false to undo this. Please note that you'll find a lot of different approaches on the internet. That's mostly because there was a change in jQuery 1.6, but since that's already an ancient version, we are not going to cover that here.